docs: def ensure_built(self, headers=None):
          """
          Make sure that a dictionary exists for this type.
          """
          if not self.params:
              return
          else:
              for child in self.params:
                  child.ensure_built(headers=headers)
          if headers is None:
              headers = self.guess_headers
          generate(str(self), headers,
                   has_iterators=self.name in HAS_ITERATORS)